Earlier, the RCMP announced in a statement that all Prince Edward Island schools were being evacuated "due to a potential threat".

Students at all primary and secondary schools across the Atlantic island province were taken to designated safe locations, federal police said, with parents anxiously awaiting information about where to pick up their children.

In Nova Scotia, meanwhile, police were probing an anonymous bomb threat against three university campuses in the province.

The campuses of Nova Scotia Community College in Halifax and in Sydney were shut after local police received the threat, about 7.50 am local time (8.50pm AEST).

Cape Breton University was also evacuated.

The US school or schools possibly also targeted were not identified by Canadian authorities.